Lifescape: Ruin and Renewal

Missouri River Basin, western Iowa

The Missouri River floodwaters
set a new stage for flora and fauna

By Terri Queck-Matzie, photos courtesy of the Iowa DNR

To the naked eye, the flood-ravaged Missouri River basin is a barren wasteland. The absence of color is omnipresent. Silt paints an overwhelming hue of pale gray across the landscape while sand blows with the wind, filling every crevice and drifting into dunes. The ground sifts through your fingertips, lifeless. Dead tree limbs dot the once-fertile fields.

There is not an animal to be seen.

“We don’t have a rodent problem any more,” says Lyle McIntosh from his farm west of Loveland. He tells of deer living atop levees during nearly four months of floodwaters that covered tens of thousands of acres in western Iowa. Doug Chafa, a wildlife biologist with the Missouri River Wildlife Management Unit of the Iowa Department of Natural Resources, remembers deer swimming from sandbar to sandbar when floodwaters were at their peak.

Those deer have since moved on to higher ground. “The numbers in the Loess Hills have increased dramatically,” says Chad Graeve, a Nature Resource Specialist with Pottawattamie County Conservation, “as have the numbers of smaller mammals.” Coyotes, groundhogs, opossums, and raccoons exited parade style to the nearby hills, leaving behind nests of young and familiar feeding grounds.

“Keep in mind,” adds Graeve, “unlike some species that require a specific type of high-quality habitat, generalist species, such as whitetail deer and raccoons, easily adapt. They’ve been adapting to the patchy landscape we humans have created for a very long time.”

Smaller bedding animals such as skunks, and the even smaller rodents, mice and moles, did not fare so well. And the exodus of land animals also meant a change of address for predators. Owls and hawks found food in the floodplain was scarce if existent at all.

But if you look beyond the death and destruction the floodwaters left behind, you will see signs of life that have not been seen for a very long time, according to Iowa Department of Natural Resources Botanist and Ecologist John Pearson. “The floods set the stage for certain species of plants and animals to recolonize, giving them an opportunity to flourish in ways they weren’t able to prior to the flood.”

More water means more fish. “As water floods the landscape, fish move to areas where there is a greater food supply and positive spawning conditions,” says Pearson. At DeSoto Bend Wildlife Refuge, an influx of river fish species into DeSoto Lake is expected to increase bluegill, crappie, and bass populations.

Graeve says they noticed the change almost immediately. Crayfish mounds appeared in extreme numbers, creating questions for biologists: Were so many simply hidden beneath the water in normal times? Or did flood waters create optimal reproductive conditions?

Salamanders and wading birds such as egrets and herons found a home in the floodwaters. “Frogs followed the edge of the water as wetlands converted to river,” explains Chafa. “They were leaping and hopping all over the place.” Pelicans were seen feeding on fish in pools at DeSoto Bend, pools where there was once dry land.

Pearson says plant life diversity increases as well. Bit by bit the barren moonscape will start turning green, populated by plant species not seen in the area since the last floodwaters receded. The delicate white flowers of whitestar morning glory (Ipomea lacunose) will appear against the background of new green. Spreading yellowcress (Rorippa sinuata) will spread its scraggly stems and leaves and yellow blooms across the sands.

“These species will be short-lived,” says Pearson, “one or maybe a few years; then they’ll be replaced by perennial vegetation. Gradually things will get back to normal as humans reclaim the land.”

“It will be interesting to see what happens now,” says Chafa. “We get to watch nature unfold.” Deer and turkeys are literally making tracks back to their old stomping grounds in the floodplain.

It is the human effects that are most highlighted by the flood’s impact on the natural landscape. “Under normal conditions the floodplain is heavily cropped,” says Pearson. “It’s a uniform habitat, planted annually, flat, and treated with herbicides that are not friendly to wild plants.”

The flooding creates a natural cleansing effect. “Human infrastructure is not meant to withstand flooding,” continues Pearson, “but natural ecosystems have been around for thousands of years. The river used to flood frequently, and whatever lives there has adapted to flooding.

“In the short term it changed the habitat,” he continues, “but it will gradually return to its former condition.”

Chafa adds there was a heavy toll on the reproductive cycle, with many young animals not surviving when adults did. But that, too, will correct itself in time. Some species, such as deer, will find added protection from hunters in the fallen trees and tangled brush the floodwaters left behind.

Because of the water, the floodplain is now ripe for rare plant species, insects, and invertebrates, and that abundance will reverberate up the food chain. “We will likely see an increase in predators the next couple of seasons because of the increased concentration of prey,” says Graeve.

New willows and cottonwoods will reforest the woodlands. That will bring a resurgence of woodcocks — a species of concern in normal times — living among the young trees. Different songbirds will sing from their growing branches. It’s all part of the give-and-take of nature.

“Floods are devastating to people and cities and farmland but not to natural habitat,” adds Pearson. “This is a turn of the page for wildlife.”